[dpdk-dev] [PATCH v6 01/10] eal: add thread id and simple thread functions

[Kinsella, Ray]

On 29/04/2021 08:44, Thomas Monjalon wrote:
> 29/04/2021 02:50, Dmitry Kozlyuk:
>> 2021-04-02 18:38 (UTC-0700), Narcisa Ana Maria Vasile:
>>> --- /dev/null
>>> +++ b/lib/librte_eal/windows/include/rte_windows_thread_types.h
>>> @@ -0,0 +1,12 @@
>>> +/* SPDX-License-Identifier: BSD-3-Clause
>>> + * Copyright(c) 2021 Microsoft Corporation
>>> + */
>>> +
>>> +#ifndef _RTE_THREAD_TYPES_H_
>>> +#define _RTE_THREAD_TYPES_H_
>>> +
>>> +#include <rte_windows.h>
>>> +
>>> +typedef DWORD                       rte_thread_t;
>>> +
>>> +#endif /* _RTE_THREAD_TYPES_H_ */
>>
>> pthread_t type in pthreads-win32 and winpthread is not 32 bit.
>> DPDK will have different ABI depending on a threading backend used.
>> Apps must know it at build time then. How do they discover it?
>> This is worth a warning in commit log and docs.
> 
> Not sure this is an acceptable behaviour.
> In my opinion, ABI should not vary.
> +Cc Ray
> 

So pthread_t on Win32 should just map to the HANDLE datatype.
Which if memory serves is in fact a DWORD on Win32. 
So I suspect that pthreads indirection is probably be just providing a circuitous route to end up in the same place, a HANDLE

IMHO
To absolutely guarantee no ABI change, we ought to be passing back void * not rte_thread_t. 

#ifdef WIN32
/* The primitives for Windows types */
..
typedef HANDLE                apr_os_thread_t; /*becomes pthread_t later*/
..

Ray K